Effective separation of palladium from simulated high level radioactive waste

Parajuli, D.; Hirota, Koichi; Seko, Noriaki

Radioactive high-level liquid waste generated during the reprocessing of spent nuclear fuel can be a rich source of a number of rare metals. Among several metals of interest, recovery of fission palladium is of particular interest for its high concentration (2000 ppm). Also, 83% of fission palladium is of stable isotopes and remaining 17% of radioactive Pd also possesses poor intrinsic radioactivity that is acceptable for several industrial applications. However, selective and effective separation of the desired fission-element is always a big challenge for even the highly efficient extractants in normal conditions lose their metal binding property when exposed to the radiation. Considering the rigidity of biomass-based adsorbents in harsh conditions, Japanese cedar wood powder was modified to thiamide-type adsorbent, CWP-TU, by microwave heating and tested for the adsorption of Pd(II) from nitric acid in normal and irradiation conditions. The results show that CWP-TU not only possesses distinct selectivity for Pd(II) in simulated high-level liquid waste, but also exhibits high loading capacity under irradiation environment as in normal condition.